We’ve left David Brooks alone for a while now, ever since the NYT decided that their op-ed columnists could generate revenue. But I’ll return to Brooks, with apologies for the impossibility of linking to the whole editorial.

As our readers know, Brooks has probably never thought up an over-simplifying sociological dichotomy that he wasn’t impressed with and convinced contained profound insights into politics and society.

In the world of public policy, there are ecologists and engineers. The ecologists believe human beings are formed amid a web of relationships. Behavior is shaped by the weave of expectations and motivations that we pick up from the people around us every day.

In contrast there are “engineers” who believe that rational behavior can be effected through offering incentives. This dichotomy like most of Brooks’ simplifications conceals more than it reveals. One suspects that most people are more like ecological engineers. But, we won’t even count the irrelevant dichotomy in his column.

Nevertheless, the object of Brook’s column is a Democratic Leadership Council plan to increase the financial resources available for College. This he claims ignores the ecology of college graduation.

A case in point: Over the past three decades there has been a gigantic effort to increase the share of Americans who graduate from college. The federal government has spent roughly $750 billion on financial aid. Yet the percentage of Americans who graduate has barely budged. The number of Americans who drop out of college leaps from year to year.

So, according to Brooks the percentage of students who graduate has barely budged and the number of College drop outs has increased, despite spending three quarters of a trillion dollars! What’s going on here?

For one thing, the number of college graduates has increased dramatically over the “past three decades.” (US Department of Education claims 5.8 million full time students in 1970 and around 10 million in 2005). So the really significant number is not the graduation rate but the number of college graduates. Thirty years ago only 47% of high school graduates attended college. In the mid-90’s it was around 66%. In addition the percentage of Americans in the workforce with a Bachelor’s degree has increased in the past ten years from 26% to 33%.

Brooks seems to be doing some fairly standard manipulation of statistics to suggest that 750 billion of tax payer money has not had any significant benefit. He may be correct. But the picture is far more complicated than he admits and his argument for this conclusion is extremely weak. We would probably call this “suppressed evidence.”

Second, it isn’t entirely clear that financial aid is thought to have such a simple relationship to graduation rates. Financial resources are obviously a necessary condition but not a sufficient condition of college graduation. The question that we would need to ask is not whether financial aid has increased the graduation rate, but whether it is affected the graduation rate. Perhaps, and indeed, quite plausibliy, without that 750 billion in financial aid many more students would not have considered attending college, or the drop-out rate might have increased.

The only evidence that Brooks offers against this is the claim that only 8% of students are “driven away by purely financial reasons.” I’m not familiar with this research, but it strikes me that “financial reasons” are rarely “purely” the cause, since struggling with finances have many other effects for students.

But as an “ecologist,” Brooks thinks that providing financial assistance for college is a insufficient condition for affecting college graduation rates.

You have to promote two-parent stable homes so children can develop the self-control they need for school success. You have to fundamentally reform schools. You have to expand church- and university-sponsored mentoring programs and support groups. As Caroline Hoxby of Harvard notes, you have to surround students with people who will help them make informed decisions so they can attend a college they find useful.

Perhaps that is so. But the impression that the only thing the DLC’s proposal amounts to is throwing money at the middle class to buy votes is a gross oversimplification of the problems of rising costs of higher education.